Pat the pork cubes dry with paper towels, then season all over with salt, black pepper, and smoked paprika. Press Saute on the Instant Pot set to More, add olive oil, and sear the pork in two or three batches in a single layer for about 3 minutes per batch until deeply browned. Transfer the seared pork to a plate and set aside, leaving the rendered fat and browned bits in the pot.
Add the diced onion and sliced celery to the pot and saute for 3 to 4 minutes until the onion softens, stirring often. Add the minced garlic and cook for 30 seconds until fragrant, then stir in the tomato paste and cook for 1 to 2 minutes, letting it darken slightly against the bottom of the pot.
Pour in the Worcestershire sauce and about half of the beef broth. Scrape the bottom of the insert thoroughly with a wooden spoon to lift every browned bit, making sure nothing is still stuck before moving on.
Return the seared pork and any juices on the plate to the pot, then pour in the rest of the beef broth. Add the potato chunks, carrot rounds, dried thyme, dried rosemary, and bay leaves, and stir gently so everything is submerged. Do not stir in the cornstarch slurry or the peas yet.
Lock the lid in place and set the valve to sealing. Select Manual or Pressure Cook on high pressure and set the timer for 30 minutes. Allow about 10 to 15 minutes for the pot to come up to pressure, then when the timer finishes, let the pressure release naturally for 10 minutes before carefully switching the valve to venting to release any remaining pressure.
Open the lid, remove and discard the bay leaves, and skim off excess surface fat if needed. Press Saute again to bring the stew to a gentle simmer, whisk the cornstarch and cold water together one more time, then stir the slurry into the simmering stew. Cook for 3 to 5 minutes, stirring, until the broth thickens enough to coat the back of a spoon, then stir in the frozen peas and cook for 2 minutes more until heated through. Turn off the pot, taste, and adjust salt and pepper, and garnish with chopped parsley before serving.